The present invention relates to a filtering apparatus for separating a substance such as slurry, sludge or other suspension into a liquid component and a solid component in such a manner that the separated solid component is obtained as a cake in semi-dried condition.
In the chemical and pharmaceutical industries, filtering apparatuses of various types have been used to separate substances such as those mentioned above into a liquid component and a solid component. On the other hand, the construction industry requires a filtering apparatus which is capable of continuously dealing with a large quantity of slurry or sludge with high efficiency, but for this purpose it is impossible to utilize the known filtering apparatuses which have been used in the chemical and pharmaceutical industries because they cannot continuously filter a large quantity of slurry or sludge with high efficiency.
One type of known filtering apparatus is of suction type in which the substance to be filtered is dealt with under a suction force in order to improve the filtering efficiency. The known apparatus also makes use of a perforated filter plate on which a filter cloth is directly supported, the total area of the perforations accounting for only 4 to 5% of the total area of the filter plate. Since with the apparatus of this arrangement the filtering efficiency tends to gradually decrease as the filtered solid component accumulates on the filter plate, the known apparatus cannot be utilized to continuously deal with a large quantity of slurry or sludge. Furthermore, the arrangement has an inherently-limited filtering efficiency because the filter cloth is directly supported on the perforated filter plate having perforations equivalent to only 4 to 5% of full area of the plate.
Therefore, it is a primary object of this invention to provide a filtering apparatus of the suction type which can be utilized to continuously deal with a large quantity of slurry, sludge or other suspension for separating it into a liquid component and a solid component in such a manner that the separated solid component is obtained as a cake in a semi-dried condition.
Another object of this invention is to provide a filtering apparatus of the above-mentioned type in which the continuous-filtering operation can be performed at high efficiency.
A further object of this invention is to provide a filtering apparatus of the above-mentioned type in which the separated solid component can be obtained as a cake in a more highly-dried condition.